Lock



M. o. BEHNKE l 2,182,307

LOCK

Filed March 24, 1937 2O al 'TORNEYS.

Patented Dec. 5, 1939 UNITED STATES PATENT OFFICE LOCK Application March 24, 1937, Serial No. 132,700

2 Claims.

This invention relates to locks of the type used for locking cabinets, cedar chests, closets, etc.

It is very desirable that a lock of this type be operable manually under certain conditions without the use of a key, and that under other conditions, the lock be rendered inoperable except by a key. While locks having this operation have been developed and used in the prior art, such .locks have usually utilized a considerable number "1b of parts and have been quite costly. By a novel ,h2/0 extreme end whereby it may be easily operated manually. The key plug has a series of tumblers and a keyway, the tumb-lers normally locking the plug to the cylinder and being retractible by key operation to release the plug from the cylinder so that the key plug may be rotated freely. When so rotated, it operates to move a locking lever to release position.

In one position of the key plug, the tumblers lock it relatively to the cylinder against any movement whatsoever. By the insertion of the key for which the tumblers are formed, the plug may be rotated in a particular direction to a second position and the key withdrawn. When in this second position, the tumblers allow limited rotation of the key plug in the same particular direction, this being sumcient to enable the plug to operate the locking lever. The tumblers prevent rotation of the key plug back into its original locked position, however, until the key is inserted once again. Thus, the key is used to put the plug in a locked position and then into an unlocked position.

Having now described my invention generally, I shall refer to the drawing for a detailed description thereof. In the drawing, Fig. 1 is an elevation of my lock, while Fig. 2 is a side View and partial section of the lock assembled relatively to a strike. Figs. 3, 4 and 6 show the relation of the locking lever to the key plug in various operating positions of the key plug. Fig. 5 shows the key plug in a position intermediate Figs. 3 and 6.

Referring now more particularly to the drawing, my lock comprises a casing I0 to which is attached a cylinder II in which is mounted a key plug I2. This key plug is preferably of the sliding tumbler type, having a series of sliding tumblers I3, best shown in Figs. 3-6 inclusive, which may be spring pressed by a series of springs I4 into a narrow locking slot I5, shown in Fig. 6J 5 and into a relatively wide locking slot I6, shown in Fig. 3.

The head of the key plug carries a knurled knob Il, whereby the key plug may be readily rotated manually. A keyway I8 is formed in the fm knob portion and in the key plug body, as is probably best shown in Figs. 1 and 2. The inner end of the key plug has a pin I9 formed thereon whereby the key plug operates a locking lever 20 pivoted at Ella and having a locking nose 2| for if; interlocking with the hook 22 of a strike 23, as will be understood by those skilled in the art.

The locking lever 20 is spring pressed by a spring 211 so as to bring its nose 2| within the locking slot of the hook 22, rotation of the key 20 plug I2 being eective through its pin I9 to move the lever 20 from its position in Figs. 1 and 3 to the position of Fig. 4 whereby to release the strike 23 from the lock.

'Ihe normal locked position of the key plug I2 25 is probably best illustrated in Fig. 6, which shows the tumblers I3 all resting in the narrow locking slot I5 and the locking lever 20 with its nose 2I in the slot of the hook 22. When a key is inserted into the keyway I8, each of the tumblers I3 is 30 retracted against the pressure of the individual tumbler springs I4 into a position entirely within the key plug, as is best illustrated in Fig. 5. Should any one of the tumblers be moved somewhat beyond the periphery of the plug, as by 35 picking, or by a wrong key, the abutment lla. will prevent rotation in the direction of the arrow to the position of Fig. 5. v

It is obvious that with the tumblers properly set the ykey plug I2 may now be rotated from its 40 position of Fig. 6 to the position of Fig. 5, and then to the position of Fig. 3, bringing the spring projected ends of the tumblers I3 opposite the wide slot I6. This motion of key plug I2 is independent of locking lever 20 which is actuated 45 only after the key plug and its pin I9 rotate beyond the position of Fig. 3. In Fig. 3, if the key is removed, all of the tumblers will press into the slot I6 under the inuence of springs I4. The slot 25 is formed to allow removal of the key, since some of the tumblers may be required to ride into the slot 25 as higher and lower bittings of the key engage the various tumblers I3, as will be understood by those skilled in the art. 55

Incidentally, in Fig. 5, the key K is shown in section engaging one of the tumblers I3.

With the parts in the position of Fig. 3, it is quite obvious that the key plug I2 may be rotated clockwise to the position of Fig. 4 from the position of Fig. 3 without the use of a key, the tumblers resting in the wide slot I 6. This movement of the key plug will of course cause pin I9 to move locking lever 20 to the release position of Fig. 4. Counterclockwise movement of key plug I2 from the position of Fig. 3 back to the positions of Figs. 5 and 6 will be quite impossible, however, since the tumblers I3 will abut the surface Ia dening one Yend of the slot I6.

If it is desired to move the key plug back into its locked position of Fig. 6, the key must be inserted, retracting the tumblers relatively to the key plug I2, to a position somewhat like that of Fig. 5, after which the key plug may be rotated to the position of Fig. 6 and the key Withdrawn.

Those well skilled in the art will readily appreciate that I am able to obtain extremely desirable 4results through my invention, while using an extrememinimum of parts. For instance, I have but a single looking lever, a single key plug with an integral pin for operating the lever, and a cylinder in which the key plug rotates. Through a novel association of the key plug, tumblers and cylinder, I am able to obtain novel operations normally obtainable only through the use of many additional parts.

I now claim:

1. In ailock of the class described, a key plug, releasing means operatedfby rotation of said key plug, a cylinder relatively to which said key plug rotates, a series of tumblers carried by said key plug and projecting into a slot in said cylinder whereby to lock said plug against rotation in said cylinder, said tumblers being of a length equal to the'diameter of the key plug and retractible by a key out of said slot whereupon said key plug is rotatable in a releasing direction to operate said releasing means, an abutment on said cylinder for preventing rotation of said key plug in a release direction if said tumblers are retracted out of said relatively narrow slot a distance projecting the tumblers beyond the key plug, said cylinder having a second slot into which said tumblers may be projected by with# lease position,va cylinder relatively to Which said key plug-rotates, a series of tumblers carried by saidkey plug and projecting into a locking slot in said cylinder whereby to lock said plug against rotation in said cylinder, said tumblers being -retractible by a key out of said locking slot whereupon said key plug is rotatable in a re- -leasing direction to operate said releasing means,

saidcylinder having a second'slot into which said tumblers may be projected by withdrawal ofthe key on-ce said key plug isfrotated a predetermined. amount from its locked position, the said key plug being adapted for yrotating said predetermined amount independently of said spring pressed locking `lever, -said lsecond slot allowing free rotation'of said key plug in a Adirection to move said locking leverto release position without the key maintaining the tumblers retracted, While cooperatingwith vthe projected tumb-lersto prevent rotation `of said key plug'back to its locked position.

MAX O. BEHNKE. 

